1. Field of the Invention
This invention relates to attitude control systems for a self-propelled interceptor.
2. Description of the Related Art
Interceptors such as self-propelled rockets, missiles or counter-missile missiles may be launched from air, land or sea-based platforms to engage a target. The interceptor may be used offensively against other platforms, fixed emplacements or other targets or defensively to intercept and destroy enemy missiles. The interceptor may use explosive or kinetic energy to defeat the target.
The interceptor is propelled by a rocket motor. Rocket propellant is ignited and burns creating a high-pressure gas. This gas is expelled in a generally axial direction through one or more main nozzles that convert the high-pressure gas into a high-velocity gas.
The interceptor is maneuvered by an attitude control system (ACS). In general, the ACS produces a “moment” offset from the center of gravity (Cg) of the interceptor that interacts with the main axial thrust vector to change the attitude of the interceptor. This moment may provide yaw, pitch and/or roll control. One approach known as “thrust vector control” uses a servo motor to physically reorient the one or more main nozzles to produce the desired moment. Another approach known as “aerodynamic control” uses servo motor to physically deploy one or more aerodynamic control surfaces such as fins. Some interceptors use a combination of thrust vector control at low speed with aerodynamic control at high speed. Another approach is to selectively ignite one or more explosive guidance units (EGUs) placed on the airframe to generate impulse moments to control the attitude. In any of these approaches, a flight control system responds to guidance commands to command the ACS to maneuver the interceptor. Guidance may be provided as a command line-of-sight (CLOS) in which a targeting system tracks the target and the interceptor, calculates the appropriate guidance commands that will result in an intercept and send these commands to the interceptor to execute, a “beamrider” in which an IR sensor mounted aft of the interceptor “rides” an IR beam from the platform to the target, or a Homing Guidance (active, semi-active or passive) in which a sensor mounted forward of the interceptor locks onto the target.